Transitional flow field characterization inside an arteriovenous graft-to-vein anastomosis under pulsatile flow conditions

The objective of this study was to investigate the relationship between the distribution of turbulence intensity and the localization of stenoses inside the venous anastomosis of arteriovenous (AV) grafts. Turbulent flow measurements were conducted inside an upscaled end-to-side graft model under pulsatile flow conditions. The pulsatile flow waveforms had maximum, minimum and mean Reynolds numbers of 2500, 1200 and 1800, respectively based on the graft diameter. The distribution of the velocity and turbulence intensity was measured at several locations in the plane of the bifurcation of the model. Turbulence intensity was found to be greatest downstream of the anastomosis. Results indicate a possible relation between the vein wall and graft vibration and the development of intimal hyperplasia which is correlated with the animal studies cited in the paper. Future studies are required to better understand the mechanism of formation of the intimal hyperplasia and the level of the turbulence.